Running wires

This week, prior to doing the actual swapping of the rear end and transmission, I'll need to run some wires for the speedo signal. In the '86, these wires are part of a whole loom, and not easily separated from the rest of the group. So I figured that instead of ripping them out, I'd just run my own. While I'm running those I'll probably also run another for the rear fogs, since I have a switch from the '86 for them... But I digress. I tried finding a wiring diagram for the speedo online, but what I did find didn't look very helpful. The speedo plug has 3 wires - black, blue and red/black, while the sender only has the black and blue. So I figure the red/black is a power wire of some kind, but I've got to figure out if it's a 12v switched or stepped down somehow before I go splicing in and scorching electronics.

At the very least I can get the bare wires plumbed into the car and put into the approximate locations before anything else happens, anyway. I wonder if I should think about running some amp wire as well while I have the carpet pulled up and seat out for this... Hmm. I may have to do just that.

Oh and I'll have to rain-x as well because I HATE HATE HATE using my wipers. Bah humbug.